1. Field of the Invention
The invention relates to an assembly that limits compressive forces when fastening one workpiece to another. More specifically, the invention relates to a compression limiting assembly capable of retaining a fastener therein before securing one workpiece to another.
2. Description of the Related Art
Pieces of manufacture, commonly referred to as xe2x80x9cworkpieces,xe2x80x9d are often secured together in a manner where two workpieces are forced to abut each other. In the environment of the motor vehicle, these workpieces have to be secured together with sufficient force to prevent the fasteners from loosening due to the vibrations, temperature and driving surface conditions.
The technologies used to fabricate materials used in such environments are sophisticated. The materials are designed to provide the greatest amount of strength and add the least amount of weight. Sacrificed in this methodology is the ability to absorb stress forces. More specifically, a material that is designed to be the light weight and strong may sacrifice strength in terms of stress.
Stress is incurred in a workpiece when it is fastened to another workpiece. The stress on a workpiece in the area immediately adjacent the fastener may exceed the capabilities thereof resulting in a cracked workpiece. An example of two workpieces that are fabricated from sophisticated materials and are secured together in a volatile environment is the combination of the the upper and lower manifolds of an internal combustion engine. The upper and lower manifolds are secured together in a manner that perfect a seal therebetween. Therefore, enough compression must be made between the two workpieces to perfect the seal without providing too much compression such that the upper and lower manifolds crack under the stress.
One attempt to solve the problem is disclosed in the U.S. Pat. No. 6,030,161, issued to Udell et al. and Feb. 29, 2000. This patent discloses a captive bolt assembly. The captive bolt assembly includes a sleeve having a flange at its distal end thereof. A bolt, the fastener, includes a head portion and a threaded portion. A collar is secured to the bolt adjacent the head portion. The collar includes a retaining portion. The retaining portion engages the inner surface of the sleeve preventing the bolt from being removed from the sleeve. The flange at the end of the sleeve acts as a compression limiter preventing the bolt from being forced into a workpiece after the flange about the surface thereof. This reference discloses that compression limiter with a retention system for the bolt. This reference does not disclose, however, an assembly providing for a bolt retainer that allows the bolt to move axially with respect to the compression limiter.
Another reference disclosing a fastener for a manifold for an internal combustion engine is U.S. Pat. No. 5,275,135, issued to Clemens et al. on Jan. 4, 1994. This reference discloses a fastener for a molded workpiece, namely an intake manifold, to another portion of the intake manifold. The fastener includes a first threaded section and a second section extending beyond the first threaded section. The second section has a diameter greater than the second threaded section. The second section defines an annular shoulder surrounding the first threaded section. While the fastener has an annular shoulder that may act as a compression limiter, nowhere in this reference is there a disclosure of a means for securing the fastener to one of the two manifolds to create a retention of the fastener during the assembly thereof.
A compression limiting assembly minimizes the compressive forces of a bolt on a first workpiece being fastened to a second workpiece. The compression limiting assembly includes a longitudinal sleeve defining a longitudinal axis extending between a first piece engaging end and a bore insertion end. The first piece engaging end includes a flange that prevents a longitudinal sleeve from fully extending into the first workpiece. A bolt retainer is housed within the longitudinal sleeve. The bolt retainer is adapted to receive the bolt therethrough to prevent the bolt from falling out of the longitudinal sleeve as the compression limiting assembly is being inserted into the first and second workpieces.